This invention relates to a coin operated timing mechanism. The mechanism is useful, for example, in the field of parking meters and like devices where, upon insertion of a coin, token or other device, a counting period or timing interval begins. The term "coin" as used hereinafter is intended to cover legal tender as well as tokens or similar devices.
The timing interval in such mechanisms is usually determined by the number and value of the coins inserted into the device. While the present invention is most specifically adapted for use as a parking meter for automobiles, it will be appreciated that the design is also intended for use in other environments. In general, the meter of the present invention can be used wherever it is desired to control a period of use depending upon the insertion of a number of coins.
Sollenberger U.S. Pat. No. 2,603,288 discloses an example of parking meters of the type which have been most widely used. Those meters employ primarily mechanical devices utilizing springs, gears, and like mechanical components to accomplish the desired purpose. A drawback in the use of solely mechanical components is the degree of servicing which is often required by such units. The parts wear and require lubrication and replacement at frequent intervals.
In the electronic field, devices for timing events have been known such as disclosed in Malott U.S. Pat. No. 4,031,991. Such meters may be more suitable for operation under severe temperature conditions, and an electronic design may increase servicing intervals. Other advantages include the ability to obtain a variety of options which are not easily implemented in mechanical meters. For example, by programming the electronics of the Malott system, each coin inserted by a user at a given time can be assigned a different value, i.e., the first quarter dollar inserted in the meter might correspond to two hours of parking time while a second quarter would correspond to one hour and a third quarter 30 minutes. Alternatively, if desired, a constant rate for each coin can be provided. An additional feature which is easily incorporated is what is referred to as MRP or "maximum revenue production" whereby when a motorist pulls into a parking space he is compelled to insert coins rather than to depend upon the time purchased by the previous user of the space.
The Malott disclosure recognizes that the rotatable handle and associated mechanism parts of a mechanical meter can be utilized for developing signals which function in an electronic system. Selby U.S. Pat. No. 3,757,916 and Shapiro U.S. Pat. No. 4,792,032 also utilize this general concept in connection with electronic parking control systems. Both the Malott and Shapiro disclosures also recognize that the traditional "flagging" functions of mechanical meters, i.e., visual displays indicating a violation or an expired time condition, are desirably incorporated in an electronic meter.
Rubenstein U.S. Pat. No. 3,930,363 and U.K. Patent Application No. 2,077,475, published Dec. 16, 1981, also disclose electronically controlled parking meters. In the latter instance, emphasis is placed on the use of CMOS (complementary metal oxide) integrated circuitry to achieve operation with low power consumption.